Mechanical time fuse



M 26, 1949. R, T, H L Y 2,471,540

MECHANICAL TIME FUSE Filed Oct. 27, 1944 7 IN VEN TOR.

WITNESS: BY

Patented July 26, 1949 MECHANICAL TIME FUSE,

Roy '1. Hurley, Westport, Conn, assignor to Bendix Aviation Corporation, South Bend, Ind, a

corporation of Delaware Application fictober 27, 1944, Serial No. 560,597

1 Claim.

The present invention relates to mechanical time fuses for artillery projectiles and more particularly to a means and method for sealing and protecting such devices from intrusion of moisture or other foreign matter.

Artillery projectiles must be usable without substantial reduction in accuracy of operation under widely variant conditions and after long periods of storage. Considerable difiiculty has been encountered however in providing satisfactory means for so protecting mechanical time fuses for projectiles that they retain their precision under all conditions and for many years. The housings for such fuses are commonly made in sections, the parting line or joint of which is liable to admit humidity or other deleterious matter, particularly where it is necessary for the parts to be capable of relative movement as in the operation of setting the timing mechanism for the fuse. The use of various coatings in the nature of varnishes or plastics has been proposed but the entry of such material into the joints to be sealed has been found to interfere with the setting and/or the retention of the timing adjustment in an undesirable manner.

It is an object of the present invention to pro vide a novel means for hermetically sealing the joints of projectiles and more particularly those containing mechanical time fuses.

It is a further object to provide such a means which is efiective with respect to any conditions liable to be encountered in transport, use or storage.

It is a further object to provide such a means which does not interfere in any way with the use or operation of the projectile, and more particularly with the setting of the timing mechanism thereof.

It is another object to provide such a means which does not obscure, but may in fact enhance the legibility of indicia appearing on the surface of the projectile.

Another object is to provide such a means which is convenient and economical to apply and is readily adaptable to various sizes and types of projectile.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation partly in vertical secticn of the housing for the fuse mechanism of an artillery projectile to which the present invention has been applied;

Fig. 2 is a perspective view of a fuse housing showing the method of applying the sealing means thereto; and v Fig. 3 is a detail of the strip or blank of material used in accomplishing the sealing operation.

In Fig. 1 of the drawing there is illustrated a fuse housing comprising an upper cap I, a lower cap 2 and a body member 3 which is threaded as indicated at 4 for insertion into the open end of an artillery shell, not illustrated, containing the base powder charge to be exploded. The upper cap 1 is threaded into the lower cap 2 as indicated at 5, the parting line or joint therebetween being indicated at E. The lower cap 2 is rotatably mounted on the body 3 by means of cylindrical portions l and 8 of the lower cap and body respectively having a close bearing fit, relative longitudinal movement being prevented by a lock ring 9. The parting line or joint between the lower cap and the body is indicated at i l.

A mechanical time fuse I2 is seated in the body 3 and retained therein by any suitable means such as the screws l3. A setting arm M is attached to the lower cap 2 by means of cap screws l5, and is arranged to engage the timing mechanism of the fuse I 2 and thereby set the fuse upon relative rotation of the lower cap 2 with respect to the body 3. In order that the setting of the fuse may be calibrated, suitable indicia such as a scale I6 and a reference line H are engraved on the body and lower cap respectively, adjacent the parting line I I.

According to the present invention means are provided for hermetically sealing the joint line 5 between the upper and lower caps of the fuse housing and the joint line H between the lower cap and body, this sealing being accomplished without obliterating or reducing the legibility of the indicia inscribed on the fuse housing. As here disclosed this is accomplished by providing strips or blanks I8 (Fig. 3) of metal foil such as aluminum or lead having suflicient ductility and being sufliciently thin to readily conform faithfully to the exterior contour and configuration of the fuse housing. These blanks are so cut as to conform substantially to the developed contour of the zones of the housing adjacent to the parting lines to be sealed and are coated on one side with a suitable adhesive which is preferably in a hardened state when the blanks are supplied to the operator for application.

The fuse housing to be sealed is preferably mounted in a rotatable holder l9 (Fig. 2) in an upright position, the coated side of the foil to be applied has been brought into wiping contact with a pad or body of absorbent material saturated with a solvent which softens the adhesive on the foil rendering it sticky or tacky. One end of the foil in this condition is then applied to the fuse housing and pressed firmly into contact therewith, and the fuse housing is rotated to wind the foil around the housing so as to cover and seal the joint. In this operation, pressure by hand or by means of suitable deformable pads;

to cause the depressions formingthe indicia to be filled with the pigment.

After the application of the foil seal, and after the adhesive has hardened by evaporation of the solvent or other action the fuse housing may if desired. be dipped or sprayed with a varnish or other preservative agent which is prevented from entering the joints by virtue of the foil seal.

It will be understood that the optimum thickness of the foil will depend to some extent on the character of the metal used and the size and configuration of the housing to be sealed. It has been found that aluminum foil having a thickness in the neighborhood of /10,0c-0 of an inch to /1000 of an inch forms a very satisfactory seal while properly conforming to the surface of the fuse housing and forming no obstacle to the settin of the fuse in the conventional manner.

Although certain materials and steps have been described as forming a preferred embodiment of the invention, it will be understood that variations therefrom which do not involve invention may be resorted to without departing from the spirit of the present invention.

What is claimed is:

In combination with a projectile having a casing comprising relatively movable parts having setting indicia formed on the surface thereof adjacent to the'joint between said parts, a foil of ductile metal cemented to the projectile and pressed into intimate contact therewith so as to cover said joint and indicia, the foil being so thin and of such ductility as to readily conform to the configuration of the surface and. thereby legibly reproduce on its exterior surface the indicia covered thereby, and a coating of varnish or the like completely enclosing the casing and foil, the foil preventing the varnish from flowing into the Joint.

ROY T. HURLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 796,271 Weiser Aug. 1, 1905 814,860 Meigs Mar. 13, 1906 1,025,647 Robinet i May '7, 1912 1,313,088 Hathaway Aug. 12, 1919 r 1,664,147 Wood Mar. 27, 1928 2,095,879 Kittredge Oct. 12, 193'? 2,1 l3,156 Kennedy Jan. 10, 1939 FOREIGN PATENTS Number Country Date 25,412 Switzerland Dec. 4, 1901 

